Is the Firefox implementation different from Chrome? I don't think Chrome allows you to default links to specific profiles but I have used this feature in Chrome for a while to separate work and personal profiles to sandbox Chrome instances.
I do all my shopping in the shopping container. I have the deals website I frequent set to the shopping container so if I open slickdeals.net in any tab, I get to the shopping container.
One quality of life change I encourage is go to manage containers and select "Select a container for each new tab". Then you can pretend the firefox tab without a container even exists (caveat: does not work with ctrl + t shortcut for new tab)
> The nice bonus feature is you can have certain sites default to containers. I had a paid YouTube account for a while, for example, so having any YouTube link open in my personal account was nice for not getting hit with ads on initial click due to my default Gmail not being the right one.